one update protects against the malware called Mac Defender that everyone claims could never happen on Apple products.
10.6.8 also fixes bugs in IPV6 that people have argued can't exist on the Apple platform.
The Airport utility update fixes crashes of Airport.
iDVD 7.1.2 fixes a long list of bugs and crashes.
As does the Aperture update , which I no longer use because of it's bugs.
But, you know, Apple is great and Jobs is god...

I highly recommend upgrading all these patches. No need to not do it. But back up your system before doing it so you can rollback if your favorite software doesn't work.

We have been having extensive problems with the new Final Cut X, which has been a fiasco of monumental proportions. The biggest failure of Apple since the Newton.